U.S. patent number 9,089,787 [Application Number 14/066,295] was granted by the patent office on 2015-07-28 for distributor in mass transfer column and method of use.
This patent grant is currently assigned to KOCH-GLITSCH, LP. The grantee listed for this patent is Koch-Glitsch, LP. Invention is credited to Darran Matthew Headley, Izak Nieuwoudt, Patrick K. Quotson.
United States Patent |
9,089,787 |
Nieuwoudt , et al. |
July 28, 2015 |
Distributor in mass transfer column and method of use
Abstract
A liquid distributor is provided for receiving and distributing
a liquid stream in a mass transfer column. The liquid distributor
has a plurality of elongated primary troughs and a plurality of
secondary troughs that are positioned adjacent the primary troughs
at a location to receive at least some of the individual primary
discharge streams from the primary troughs. Splash baffles are
spaced a preselected distance from liquid discharge holes in the
side walls of the secondary troughs to receive at least some of the
individual secondary discharge streams and cause a lateral
spreading thereof as the individual second discharge streams
descend along the splash baffles and drip from lower edges
thereof.
Inventors: |
Nieuwoudt; Izak (Wichita,
KS), Headley; Darran Matthew (Valley Center, KS),
Quotson; Patrick K. (Wichita, KS) |
Applicant: |
Name |
City |
State |
Country |
Type |
Koch-Glitsch, LP |
Wichita |
KS |
US |
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Assignee: |
KOCH-GLITSCH, LP (Wichita,
KS)
|
Family
ID: |
50929543 |
Appl.
No.: |
14/066,295 |
Filed: |
October 29, 2013 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20140166110 A1 |
Jun 19, 2014 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61737517 |
Dec 14, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28F
25/04 (20130101); B01D 3/20 (20130101); B01D
3/008 (20130101); B01F 3/04007 (20130101); Y10T
137/0318 (20150401) |
Current International
Class: |
B01F
3/04 (20060101); B01D 3/20 (20060101); B01D
3/00 (20060101) |
Field of
Search: |
;261/97,110,112.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
International Search Report and Written Opinion for
PCT/US2013/067677, dated Mar. 6, 2014, 6 pages. cited by
applicant.
|
Primary Examiner: Bushey; Charles
Attorney, Agent or Firm: MacKenzie; Stephen J.
Claims
What is claimed is:
1. A liquid distributor for receiving and distributing a liquid
stream, said liquid distributor comprising: a plurality of
elongated primary troughs positioned in side-by-side and generally
parallel relationship, each of said primary troughs having spaced
apart side walls interconnected by a floor for receiving and
allowing the accumulation of a portion of the liquid stream within
each primary trough; a plurality of liquid discharge holes in at
least one of the side walls of each of said primary troughs through
which the portion of the liquid stream that has accumulated within
each primary trough may be discharged from the associated trough in
individual primary discharge streams; a plurality of secondary
troughs having spaced apart side walls interconnected by a floor
for receiving and allowing the accumulation of a portion of the
primary discharge streams within each secondary trough, each
secondary trough being positioned adjacent one of the primary
troughs at a location to receive at least some of the individual
primary discharge streams from said one of the primary troughs; a
plurality of liquid discharge holes in at least one of the side
walls of each of the secondary troughs through which the portion of
the individual primary discharge streams that has accumulated
within each second trough may be discharged from the associated
secondary trough in individual secondary discharge streams; and
splash baffles spaced a preselected distance from at least some of
the plurality of liquid discharge holes in the side walls of the
secondary troughs to receive at least some of the individual
secondary discharge streams and cause a lateral spreading thereof
as the individual second discharge streams descend along the splash
baffles and drip from lower edges thereof.
2. The liquid distributor of claim 1, wherein each of said
secondary troughs extends parallel with and is connected to or
closely spaced from one of said primary troughs.
3. The liquid distributor of claim 1, wherein each of said
secondary troughs extends at an angle to one of said primary
troughs.
4. The liquid distributor of claim 1, wherein each of said
secondary troughs extends perpendicularly to one of said primary
troughs.
5. The liquid distributor of claim 1, wherein said splash baffles
include surface texturing to facilitate said lateral spreading of
the individual secondary discharge streams.
6. The liquid distributor of claim 1, wherein each of said splash
baffles comprises a support sheet and a texturized sheet connected
to the support sheet.
7. The liquid distributor of claim 1, wherein an undersurface of
said floors of the second troughs contains structures to inhibit
the flow of liquid along said undersurface.
8. A liquid distributor for receiving and distributing a liquid
stream, said liquid distributor comprising: a plurality of
elongated primary troughs positioned in side-by-side and generally
parallel relationship, each of said primary troughs having spaced
apart side walls interconnected by a floor for receiving and
allowing the accumulation of a portion of the liquid stream within
each primary trough; a plurality of liquid discharge holes in at
least one of the side walls of each of said primary troughs through
which the portion of the liquid stream that has accumulated within
each primary trough may be discharged from the associated trough in
individual primary discharge streams; a plurality of secondary
troughs having spaced apart side walls interconnected by a floor
for receiving and allowing the accumulation of a portion of the
primary discharge streams within each secondary trough, each
secondary trough being positioned adjacent one of the primary
troughs at a location to receive at least some of the individual
primary discharge streams from said one of the primary troughs; a
plurality of liquid discharge holes in at least one of the side
walls of each of the secondary troughs through which the portion of
the individual primary discharge streams that has accumulated
within each second trough may be discharged from the associated
secondary trough in individual secondary discharge streams; splash
baffles spaced a preselected distance from at least some of the
plurality of liquid discharge holes in the side walls of the
secondary troughs to receive at least some of the individual
secondary discharge streams and cause a lateral spreading thereof
as the individual second discharge streams descend along the splash
baffles and drip from lower edges thereof; and structures contained
on an undersurface of said floors of the second troughs to inhibit
the flow of liquid along said undersurface, wherein said structures
comprise dimples.
9. A liquid distributor for receiving and distributing a liquid
stream, said liquid distributor comprising: a plurality of
elongated primary troughs positioned in side-by-side and generally
parallel relationship, each of said primary troughs having spaced
apart side walls interconnected by a floor for receiving and
allowing the accumulation of a portion of the liquid stream within
each primary trough; a plurality of liquid discharge holes in at
least one of the side walls of each of said primary troughs through
which the portion of the liquid stream that has accumulated within
each primary trough may be discharged from the associated trough in
individual primary discharge streams; a plurality of secondary
troughs having spaced apart side walls interconnected by a floor
for receiving and allowing the accumulation of a portion of the
primary discharge streams within each secondary trough, each
secondary trough being positioned adjacent one of the primary
troughs at a location to receive at least some of the individual
primary discharge streams from said one of the primary troughs; a
plurality of liquid discharge holes in at least one of the side
walls of each of the secondary troughs through which the portion of
the individual primary discharge streams that has accumulated
within each second trough may be discharged from the associated
secondary trough in individual secondary discharge streams; splash
baffles spaced a preselected distance from at least some of the
plurality of liquid discharge holes in the side walls of the
secondary troughs to receive at least some of the individual
secondary discharge streams and cause a lateral spreading thereof
as the individual second discharge streams descend along the splash
baffles and drip from lower edges thereof; and inlet holes in the
side walls of the secondary troughs adjacent to the side walls of
the primary troughs, said inlet holes being in alignment with the
liquid discharge holes in the side walls of the primary
troughs.
10. The liquid distributor of claim 1, wherein the side walls of
the secondary troughs containing said liquid discharge holes each
includes a lower panel that angles toward the associated primary
trough, and wherein the liquid discharge holes in the side walls of
the secondary troughs are located in said lower panel.
11. The liquid distributor of claim 1, including spacer elements
positioned between the side walls of the secondary troughs and the
splash baffles.
12. A liquid distributor for receiving and distributing a liquid
stream, said liquid distributor comprising: a plurality of
elongated primary troughs positioned in side-by-side and generally
parallel relationship, each of said primary troughs having spaced
apart side walls interconnected by a floor for receiving and
allowing the accumulation of a portion of the liquid stream within
each primary trough; a plurality of liquid discharge holes in at
least one of the side walls of each of said primary troughs through
which the portion of the liquid stream that has accumulated within
each primary trough may be discharged from the associated trough in
individual primary discharge streams; a plurality of secondary
troughs having spaced apart side walls interconnected by a floor
for receiving and allowing the accumulation of a portion of the
primary discharge streams within each secondary trough, each
secondary trough being positioned adjacent one of the primary
troughs at a location to receive at least some of the individual
primary discharge streams from said one of the primary troughs; a
plurality of liquid discharge holes in at least one of the side
walls of each of the secondary troughs through which the portion of
the individual primary discharge streams that has accumulated
within each second trough may be discharged from the associated
secondary trough in individual secondary discharge streams; splash
baffles spaced a preselected distance from at least some of the
plurality of liquid discharge holes in the side walls of the
secondary troughs to receive at least some of the individual
secondary discharge streams and cause a lateral spreading thereof
as the individual second discharge streams descend along the splash
baffles and drip from lower edges thereof; and spacer elements
positioned between the side walls of the secondary troughs and the
splash baffles, wherein the spacer elements comprise dimples formed
in the side walls of the secondary troughs.
13. A method of distributing liquid to a layer of mass transfer
devices positioned in a mass transfer column using a liquid
distributor having a plurality of elongated primary troughs
positioned in side-by-side and generally parallel relationship and
a plurality of secondary troughs, each of said secondary troughs
being positioned adjacent one of said primary troughs, said method
comprising: receiving a liquid stream in said primary troughs of
said liquid distributor and allowing the liquid stream to
accumulate within the primary troughs; discharging said liquid
stream from said primary troughs through liquid discharge holes
provided in at least one side wall of each primary troughs;
receiving in said secondary troughs said liquid stream discharged
from said primary troughs and allowing said liquid stream to
accumulate within the secondary troughs; discharging said liquid
stream from said secondary troughs through liquid discharge holes
provided in at least one side wall of each secondary trough;
receiving said liquid stream discharged from said secondary troughs
on splash baffles spaced a preselected distance from said liquid
discharge holes provided in said one side wall of said secondary
troughs; causing said liquid stream received on said splash baffles
to spread laterally as it descends on said splash baffles; and
dripping said liquid stream off lower edges of said splash baffles
and into an underlying layer of said mass transfer devices.
14. The method of claim 13, including receiving said liquid stream
in a parting box positioned on top of the primary troughs and
delivering the liquid stream into the primary troughs from said
parting box.
15. The method of claim 13, wherein said liquid stream is
discharged from said primary troughs in a plurality of individual
primary discharge streams.
16. The method of claim 15, wherein said liquid stream is
discharged from said secondary troughs through individual second
discharge streams.
17. A method of distributing liquid to a layer of mass transfer
devices positioned in a mass transfer column using a liquid
distributor having a plurality of elongated primary troughs
positioned in side-by-side and generally parallel relationship and
a plurality of secondary troughs, each of said secondary troughs
being positioned adjacent one of said primary troughs, said method
comprising: receiving a liquid stream in said primary troughs of
said liquid distributor and allowing the liquid stream to
accumulate within the primary troughs; discharging said liquid
stream from said primary troughs through liquid discharge holes
provided in at least one side wall of each primary trough;
receiving in said secondary troughs said liquid stream discharged
from said primary troughs and allowing said liquid stream to
accumulate within the secondary troughs; discharging said liquid
stream from said secondary troughs through liquid discharge holes
provided in at least one side wall of each secondary trough;
receiving said liquid stream discharged from said secondary troughs
on splash baffles spaced a preselected distance from said liquid
discharge holes provided in said one side wall of said secondary
troughs; causing said liquid stream received on said splash baffles
to spread laterally as it descends on said splash baffles; and
dripping said liquid stream off lower edges of said splash baffles
and into an underlying layer of said mass transfer devices, wherein
said liquid stream is discharged from said secondary troughs
through individual second discharge streams, wherein the individual
primary discharge streams enter said secondary troughs through
inlet holes in side walls of the secondary troughs opposite from
said at least one of the side walls of the secondary troughs
containing liquid discharge holes.
18. The method of claim 16, wherein the individual primary
discharge streams enter said secondary troughs through an open top
of the secondary troughs.
19. The method of claim 16, including discharging said liquid
stream from said secondary troughs through liquid discharge holes
provided in two of the side walls of each secondary trough.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to columns in which mass
transfer and heat exchange occur and, more particularly, to liquid
distributors used in such columns and methods of liquid
distribution using such liquid distributors.
As used herein, the term "mass transfer column" refers to a column
in which mass transfer and/or heat exchanger occur. Examples of
mass transfer columns include distillation, absorption, stripping,
and extraction columns.
In mass transfer columns, one or more liquid and/or vapor streams
are brought into contact with each other to effect mass transfer
and/or heat exchange between the liquid and/or vapor streams. Beds
of structured or random packing are normally used in such mass
transfer columns to facilitate intimate contact between the liquid
and/or vapor streams and thereby enhance the desired mass transfer
and/or heat exchange between the streams. In liquid/vapor systems,
the liquid stream descends through the bed of packing and the vapor
stream ascends through the packing bed. Similarly, in liquid/liquid
and vapor/vapor systems, the denser phase descends through the bed
and the less dense phase ascends through the bed.
Uniform distribution of the descending liquid stream across the
horizontal cross section of the bed of structured or random packing
is important in order to maintain a uniform interaction between the
liquid stream and the ascending vapor stream. Various types of
liquid distributors are used in an attempt to provide a uniform
distribution of the liquid stream as it enters the top of the bed
of packing material. In one type of liquid distributor, a feed box
or parting box receives a liquid stream from an overlying collector
or a feed line and distributes it to a number of elongated and
parallel troughs that underlie or extend horizontally from the
parting box. Spaced-apart holes are formed in the side walls of the
troughs to allow liquid to exit the troughs in individual liquid
streams. Splash baffles are spaced outwardly from and parallel to
the side walls of the troughs so that the individual liquid streams
exiting the troughs through the holes are directed onto the splash
baffles. The individual liquid streams then descend along and
spread across the splash baffles before dripping off the lower edge
of the baffles into the bed of packing material. Examples of liquid
distributors of this type are shown in U.S. Pat. Nos. 6,722,639 and
7,125,004.
When designing the liquid distributors described above, the number
and size of the holes in the side walls of the trough is selected
based on the anticipated volumetric flow rate of the liquid stream
into the troughs. The total open area presented by the holes must
be designed to permit a sufficient liquid head to develop within
the troughs and thereby generate the necessary force to cause the
individual liquid streams to exit the holes with enough momentum to
reach the outwardly-spaced splash baffles. When the designed liquid
volumetric flow rate is low, the total flow capacity of the holes
must be reduced to allow a sufficient liquid head to develop in the
troughs. This reduction in flow capacity can be achieved by
reducing the size of the holes and/or by increasing the spacing
between adjacent holes to reduce the total number of holes. Both of
these options create potential disadvantages. If smaller holes are
selected, they are more likely to become clogged, thereby creating
regions on the splash baffles and in the underling packing that are
not wetted by the individual liquid streams. Similarly, if the
spacing between the holes is increased, the individual liquid
streams may not merge as they descend along and spread across the
splash baffles. A need has thus developed for a liquid distributor
that overcomes these potential disadvantages.
SUMMARY OF THE INVENTION
In one aspect, the present invention is directed to a liquid
distributor for receiving and distributing a liquid stream, such as
to an underlying layer of mass transfer devices. The liquid
distributor comprises a plurality of elongated primary troughs
positioned in side-by-side and generally parallel relationship,
each of the primary troughs having spaced apart side walls
interconnected by a floor for receiving and allowing the
accumulation of a portion of the liquid stream within each primary
trough. A plurality of liquid discharge holes are provided in at
least one of the side walls of each of said primary troughs so that
the portion of the liquid stream that has accumulated within each
primary trough may be discharged from the associated trough in
individual primary discharge streams. The liquid distributor also
includes a plurality of secondary troughs having spaced apart side
walls interconnected by a floor for receiving and allowing the
accumulation of a portion of the primary discharge streams within
each secondary trough. Each secondary trough is positioned adjacent
one of the primary troughs at a location to receive at least some
of the individual primary discharge streams from one of the primary
troughs. A plurality of liquid discharge holes are provided in at
least one of the side walls of each of the secondary troughs
through so that the portion of the individual primary discharge
streams that has accumulated with each second trough may be
discharged from the associated secondary trough in individual
secondary discharge streams. The liquid distributor further
includes splash baffles spaced a preselected distance from at least
some of the plurality of liquid discharge holes in the side walls
of the secondary troughs to receive at least some of the individual
secondary discharge streams and cause a lateral spreading thereof
as the individual second discharge streams descend along the splash
baffles and drip from lower edges thereof.
In another aspect, the invention is directed to a method of
distributing liquid to a layer of mass transfer devices using a
liquid distributor as described above.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side perspective view of a mass transfer column with
portions of a shell of the mass transfer column broken away to show
a liquid distributor of the present invention and a layer of mass
transfer devices in an open internal region;
FIG. 2 is a side perspective view of the embodiment of the liquid
distributor shown in FIG. 1, with portions of a parting box broken
away to show internal details;
FIG. 3 is an end perspective view of one embodiment of the primary
and secondary troughs and splash baffle used in the liquid
distributor, with portions of the primary trough broken away to
show internal details;
FIG. 4 is a front perspective of the embodiment of the primary and
secondary troughs and splash baffle shown in FIG. 3, with portions
of the splash baffle and secondary trough broken away;
FIG. 5 is an end elevation view illustrating the liquid flow
through the embodiment of the primary and secondary troughs shown
in FIGS. 3 and 4; and
FIG. 6 is a top perspective view of an alternate embodiment of the
liquid distributor.
DETAILED DESCRIPTION
Turning now to the drawings in greater detail and initially to FIG.
1, a mass transfer column is represented broadly by the numeral 10
and includes an upright cylindrical shell 12 that defines an open
interior region 14. A liquid distributor 16 of the present
invention is positioned in the open interior region 14 and is used
to distribute a descending liquid stream uniformly across the upper
end of one or more layers 18 of mass transfer devices such as
structured, grid or random packing material. The liquid stream then
descends through the layer(s) 18 of mass transfer devices for mass
and/or heat transfer with a vapor stream ascending through the
layer(s) 18 of mass transfer devices.
The mass transfer column 10 is of a type used to process liquid and
vapor streams to obtain fractionation or other products. Although
the shell 12 of the column 10 is shown in a cylindrical
configuration, other shapes may be used. The shell 12 is of any
suitable diameter and height and is constructed from rigid
materials that are preferably inert to or are otherwise compatible
with the fluids, temperatures, and pressures present within the
column 10.
Liquid streams 20 are directed to the column 10 through feed lines
22a and 22b positioned at appropriate locations along the height of
the column 10. Feed line 22a normally carries only liquid and feed
line 22b may carry liquid, vapor and a mixture of liquid and vapor.
Although only two liquid feed lines 22a and 22b are shown in the
drawings for simplicity of illustration, it will be appreciated
that additional liquid feed lines may be utilized if desired.
Similarly, only one vapor feed line 24 carrying a vapor stream 26
is illustrated, but additional vapor feed lines can be included if
necessary or desired for the vapor and liquid processing occurring
within the column 10. It will also be appreciated that the vapor
stream 26 can be generated within the column 10 rather than being
introduced into the column 10 through the feed line 24. The column
10 further includes an overhead line 28 for removing a vapor
product or byproduct 30 from the column 10. A bottom stream takeoff
line 32 is provided for removing a liquid product or byproduct 34
from the column 10. Other column components such as reflux stream
lines, reboilers, condensers, vapor horns, and the like may be
present, but are not illustrated because they are convenient in
nature and are not believed to be necessary for an understanding of
the present invention.
Turning additionally to FIGS. 2-5, one embodiment of the liquid
distributor 16 of the present invention includes an elongated
central parting box 36 that receives a descending liquid stream,
such as the liquid stream 20 that has been delivered by the feed
line 22a to the open internal region 14 within the shell 12 of the
column 10. The parting box 36 need not receive the liquid stream 20
directly from the feed line 22a. Instead, the liquid stream 20 may
first be subjected to one or more processing steps and then
collected by a conventional liquid collector (not shown) for
subsequent delivery to the parting box 36.
In one embodiment, the parting box 36 extends in a first direction
along a central horizontal axis or diameter of the shell 12 of the
column 10. The parting box 36 has a longitudinal length that is
approximately the same as the diameter of the shell 12 or a
substantial portion of the diameter. Instead of a single parting
box 36, more than one parting box 36 may be used, in which event
the parting boxes 36 extend in parallel and co-planar relationship
along imaginary chords of the shell 12.
The parting box 36 has a rectilinear cross section with parallel
and spaced-apart side walls 38 and 40 that extend along the long
dimension of the parting box 36 and parallel and spaced-apart side
walls 42 and 44 that extend along the short dimension or ends of
the parting box 36. A floor 46 is joined to the lower edges and an
optional cover 48 is joined to the upper edges of the side walls
40, 42, 44, and 46. The optional cover 48 includes an opening 50
through which the liquid stream 20 is delivered to the interior of
the parting box 36.
The parting box 36 feeds liquid to a plurality of elongated primary
troughs 52 that extend in spaced-apart, generally parallel and
co-planar relationship to each other. The primary troughs 52 extend
along their longitudinal length at an angle, such as an angle of
90.degree., to the longitudinal length of the parting box 36. The
primary troughs 52 each have a longitudinal length sufficient to
extend across all or a substantial portion of the cross section of
the shell 12 at their locational placement. The number of and
lateral spacing between adjacent primary troughs 52 is selected to
provide the desired liquid drip-point density in the underlying
layer 18 of mass transfer devices.
In one embodiment, each primary trough 52 is of generally
rectilinear cross section and is constructed with parallel and
spaced-apart side walls 54 and 56 that extend along the long
dimension of the primary trough 52, parallel and spaced-apart side
walls 58 and 60 that extend along the short dimension or ends of
the primary troughs 52, and a floor 62 that is joined to the lower
edges of the side walls 54, 56, 58, and 60.
In the illustrated embodiment, the parting box 36 is positioned on
top of the primary troughs 52 and the liquid in the parting box 36
is delivered to the interior of the primary troughs 52 through
openings 63 positioned in the floor 46 of the parting box 36.
Openings (not shown) may be provided in the side walls 38 and 40 of
the parting box 36 to provide an additional or alternative route
for liquid to exit the parting box 36 and flow downwardly into the
primary troughs 52.
In another embodiment, the parting box 36 and the primary troughs
52 may be positioned in generally co-planar relationship with the
primary troughs 52 extending outwardly from the side walls 38 and
40 of the parting box 36. In this embodiment, openings are provided
in the side walls 38 and 40 of the parting box 36 to allow liquid
to flow from the parting box 36 to the primary troughs 52.
A plurality of liquid discharge holes 64 are provided at the same
elevation above the floor 62 in one or both of the longer side
walls 54 and 56 of each primary trough 52. The liquid discharge
holes 64 can be of any desired shape, such as circular, triangular
or vertically elongated. The size, number and spacing of the liquid
discharge holes 64 are selected to accommodate the designed
volumetric flow rate of liquid into the primary troughs 52 so that
liquid does not overflow the top of the primary troughs 52 during
normal operational conditions. Overflow holes 66 or slots may be
provided in the side walls 54 and 56 at a level above the liquid
discharge holes 64 to allow for the controlled discharge of excess
liquid that accumulates within the primary troughs 52 when the
liquid flow rate into the primary troughs 52 exceeds the flow
capacity of the liquid discharge holes 64.
Each primary trough 52 is paired with a secondary trough 68 that is
positioned to receive liquid exiting the primary trough 52 through
the liquid discharge holes 64 in the side wall 54 or side wall 56.
When both of the side walls 54 and 56 of the primary trough 52
contain liquid discharge holes 64, secondary troughs 68 are
positioned along both of the side walls 54 and 56 or a single
secondary trough 68 is positioned to receive liquid from the liquid
discharge holes 64 in both of the side walls 54 and 56. Each
secondary trough 68 is generally rectilinear in cross section and
has a longitudinal length that is the same or approximately the
same as that of the paired primary trough 52. The secondary troughs
68 each have spaced-apart and parallel side walls 70 and 72 that
extend along the long dimension of the secondary troughs 68,
spaced-apart and parallel side walls 74 and 76 that extend along
the short dimension or ends of the secondary troughs, and a floor
78 that is joined to a lower edge of the side walls 70, 72, 74, and
76.
In one embodiment, the side wall 70 of the secondary trough 68 that
faces and is adjacent the side wall 54 or 56 of the primary trough
52 having the liquid discharge holes 64 is in contact with and
joined to the side wall 54 or 56 of the primary trough 52. In
another embodiment, the side wall 70 of the secondary trough 68 is
closely spaced from the side wall 54 or 56 of the primary trough 52
by a distance that still permits liquid exiting from the liquid
discharge holes 64 to enter the paired secondary trough 68. The
side wall 70 of the secondary trough has inlet holes 80 aligned
with the liquid discharge holes 64 in the side wall 54 or 56 of the
primary trough 52. Alternatively, the top edge of the side wall 70
is positioned below the level of the liquid discharge holes 64 in
the side wall 54 or 56 of the primary trough 52 so that liquid
exiting the primary trough 52 through the liquid discharge holes 64
enters the secondary trough 68 through is its open top.
The side wall 72 of each secondary trough 52 that is opposite from
the side wall 70 that is adjacent to the primary trough 52 has a
plurality of liquid discharge holes 82. The liquid discharge holes
82 can be of any desired shape, such as circular, triangular or
vertically elongated. The size, number and spacing of the liquid
discharge holes 82 are selected to accommodate the designed
volumetric flow rate of liquid into the secondary troughs 68 so
that liquid does not overflow the top of the secondary troughs 68
during normal operational conditions. The liquid discharge holes 82
are each positioned at the desired and normally the same elevation
in the side wall 72. In the illustrated embodiment, the liquid
discharge holes 82 are located in a lower portion 84 of the side
wall 72 that is bent away from a vertical plane at a preselected
angle toward the opposite side wall 70 and the primary trough 52.
The floor 78 slopes downwardly from the opposite side wall 70
toward the lower portion 84 of the side wall 72 so that the floor
78 directs liquid toward the liquid discharge holes 82. Overflow
holes 86 or slots may be provided in the side wall 72 at a level
above the liquid discharge holes 82 to allow for the controlled
discharge of excess liquid that accumulates within the secondary
troughs 68 when the liquid flow rate into the secondary troughs 68
exceeds the flow capacity of the liquid discharge holes 82.
A plurality of spaced-apart dimples 88 extend downwardly on an
undersurface of the floor 78 and the lower portion 84 of the side
wall 72. The dimples 88 are placed between adjacent liquid
discharge holes 82 to create drip points that interrupt the
longitudinal flow of liquid along the undersurface of the floor 78
and the lower portion 84 of the side wall 72. The liquid discharge
holes 82 can also be formed by punching to create a slight burr
surrounding the liquid discharge holes 82 to reduce the opportunity
for liquid to track along the outer surface of the side wall
72.
A splash baffle 90 is positioned adjacent each secondary trough 52
at a location to receive the liquid that exits the secondary trough
52 through the liquid discharge holes 82. The splash baffle 90
extends longitudinally along all or substantially all of the
longitudinal length of the secondary trough 52. In one embodiment,
the splash baffle 90 has a planar upper segment 92 that extends
vertically along the side wall 72, a planar intermediate segment 94
that is angled to underlie the secondary trough, and a planar lower
segment 96 that extends vertically downward below the associated
primary trough 52 and has a serrated bottom edge. Spacer dimples 98
that extend outwardly from the side wall 72 of the secondary trough
68 are in contact with the upper segment 92 of the splash baffle 90
to create a slight spacing between the upper segment 92 and the
side wall 72.
The upper segment 92 of the splash baffle 90 extends a preselected
distance below the secondary trough 68 so that the intermediate
portion 94 of the splash baffle 90 is spaced a preselected distance
below the liquid discharge holes 82. This spacing between the
intermediate portion 94 and the liquid discharge holes 82 creates
an outlet clearance for liquid to exit the liquid discharge holes
82. In embodiments where the lower portion 84 of the side wall 72
is not bent away from the vertical, additional spacing must be
provided between the liquid discharge holes 82 and the upper
portion of the splash baffle 90 to provide the necessary outlet
clearance.
A planar vertical baffle 100 extends downwardly from the side wall
56 of each primary trough 52 a sufficient distance so that its
lower region is spaced horizontally from the lower segment 96 of
the splash baffle 90 to form an elongated liquid discharge outlet
102 that underlies the longitudinal length of the primary trough
52. In embodiments where secondary troughs 68 are positioned along
both of the side walls 54 and 56 of the primary trough 52, the
baffle 100 is not used and the liquid discharge outlet 102 is
formed by the lower segments 96 of the two splash baffles 90 that
are mirror images of each other.
The secondary troughs 68 may be in the same plane as the primary
troughs 52 or the secondary trough 68 may be displaced somewhat
from the plane of the primary troughs 52 so that at least a portion
of the secondary troughs 68 extends below the primary troughs 52.
The internal volume of the secondary trough 68 in one embodiment is
less than that of the primary troughs 52. The total liquid flow
capacity of the liquid discharge holes 64 in the side walls 54
and/or 56 of the primary troughs 52 may be the same, greater than,
or less than that of the liquid discharge holes 82 in the side
walls 72 of the secondary troughs 68. Normally, however, the number
of liquid discharge holes 82 in the side walls 72 of the secondary
troughs 68 is greater than the number of liquid discharge holes 64
in the side walls 54 and/or 56 of the primary troughs 52 so that
the secondary troughs 68 act as flow multipliers to increase the
lateral spreading of the liquid on the splash baffles 90.
As shown in FIG. 2, two beams 108 are equally spaced on opposite
sides of the parting box 36 and are welded or otherwise secured to
the top edges of the primary troughs 52. The beams 108 support and
align the primary troughs 52. Support clips 110 are positioned at
the ends of the beams 108 and the parting box 36 and may be secured
to a support ring (not shown) or other structure that is attached
to the shell 12 of the column 10. Other methods of supporting the
liquid distributor 16, such as grid supports placed on the
underlying layer 18 of mass transfer devices, can be used in place
of or in addition to the support clips 110. The beams 108 and
support clips 110 are not shown in FIG. 1 to simplify that
illustration of the liquid distributor 16.
As can be seen with reference to FIG. 5, liquid that has been
delivered to one of the primary troughs 52 by the parting box 36
(not shown in FIG. 5), accumulates within the primary trough 52.
When the level of accumulated liquid reaches or exceeds the
elevation of the liquid discharge holes 64 in the side wall 54, the
liquid is discharged into the secondary trough 68 through the
liquid discharge holes 64 and through the inlet holes 80. The
liquid is discharged as individual primary liquid streams designed
by the arrow 104. The liquid from the individual primary liquid
streams 104 accumulates within the secondary troughs 68 and is
directed by the floor 78 to the liquid discharge openings 82 in the
lower portion 84 of side wall 72. The liquid is then discharged
from the secondary troughs 68 through the liquid discharge openings
82 as individual secondary liquid streams designed by the arrow
106. Any overflow from the secondary troughs 68 exits through the
overflow holes or slots 86 and descends in the spacing between the
side wall 72 and the upper segment 92 of the splash baffle 90.
The individual secondary liquid streams 106 are directed against
the splash baffle 90 and then descend and spread laterally along
the surface of the splash baffle 90. In one embodiment, the surface
of the splash baffle 90 is treated with surface texturing to
facilitate the lateral spread of the liquid. In another embodiment,
the surface texturing is provided on a thinner layer of material
that is more easily worked and is then laminated onto the surface
of the splash baffle 90. Once the liquid reaches the lower
discharge outlet 102, it forms a continuous curtain of liquid that
drips or flows into the underlying layer 18 of mass transfer
devices (not shown in FIG. 5).
It can be seen that the use of the secondary troughs 68 allows
larger liquid discharge holes 64 that are spaced further apart to
be provided in the side walls 54 and/or 56 of the primary troughs
52 even in applications where the liquid distributor 16 is designed
for low liquid flow conditions. The larger liquid discharge holes
64 are advantageous in that they are less prone to becoming
plugged, such as by debris or scale. The secondary troughs 68 serve
to cause greater lateral spreading of the liquid on the splash
baffles 90 than would otherwise result from flowing the liquid
directly from the primary baffles 52 onto the splash baffles
90.
Turning now to FIG. 6, another embodiment of the liquid distributor
of the present invention is shown and is designated generally by
the numeral 216. Liquid distributor 216 has many of the same
components as the liquid distributor 16 previously described and
the same reference numerals with the prefix "2" are used to
designate like components. Liquid distributor comprises a parting
box 236 constructed in the same manner as the parting box 36
previously described and primary troughs 252 that are the same as
primary troughs 52. The liquid distributor 216 further comprises
secondary troughs 268 that are generally of the same constructions
as secondary troughs 68 except they extend perpendicular to the
primary troughs 252 and liquid does not feed into the secondary
troughs 268 through inlet holes in a side wall 270 of the secondary
troughs 268 as is the case with the secondary troughs 68 of the
first embodiment.
Instead, in one embodiment, liquid feeds into the secondary troughs
268 through an open end of the secondary trough 268 that abuts a
side wall 254 or 256 of the primary trough 252. Liquid discharge
holes 264 in the side walls 254 and 256 of the primary trough 252
allow the liquid to exit the primary troughs 252 as individual
primary liquid streams and enter the associated secondary troughs
268. In the illustrated embodiment, a cutout 269 is provided in the
side walls 70 and 72 of each secondary trough 268 to receive the
primary trough 252 so that liquid is additionally able to enter the
secondary troughs 268 through holes (not shown) in a floor 262 of
each primary trough 252. The liquid then exits the secondary
troughs 268 and impacts and flows down splash baffles 290 in the
same manner as previously described for delivery as a continuous
curtain of liquid into an underlying layer (not shown) of mass
transfer devices. Two splash baffles 290 are provided for each
secondary trough 268 when liquid is discharged from both side walls
270 and 272. When liquid is only discharged through one of the side
walls 270 or 272, a single splash baffle 290 is used in combination
with a planar baffle, such as the baffle 100 used in the liquid
distributor 16 described above.
Because the secondary troughs extend at a perpendicular or other
angle to the primary troughs 252 in the liquid distributor 216, the
number of secondary troughs 268 can be selected independently of
the number of primary troughs 252. In both embodiments of the
liquid distributor 16 and 216, separate secondary troughs 68 and
268 may be associated with each of the liquid discharge holes 64
and 264 in the associated primary troughs 52 and 252.
From the foregoing, it will be seen that this invention is one well
adapted to attain all the ends and objectives hereinabove set forth
together with other advantages that are inherent to the
structure.
It will be understood that certain features and subcombinations are
of utility and may be employed without reference to other features
and subcombinations. This is contemplated by and is within the
scope of the invention.
Since many possible embodiments may be made of the invention
without departing from the scope thereof, it is to be understood
that all matter herein set forth or shown in the accompanying
drawings is to be interpreted as illustrative and not in a limiting
sense.
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